"Effy" is the seventh episode of Series 4 and the 36th episode overall.

This episode primarily focuses on Effy Stonem and her attempts to deal with her mental illness, along with her feelings over the events of "Series Finale", something she had never previously discussed, and how her "alternative" counselling with John Foster effects her relationship with the group.

Effy has been submitted to a psychiatric hospital where her counselor, John Foster, asks her about her brother, Tony. After three weeks, she finally tells him about the events of the episode "Series Finale" where Tony is hit by a bus. Foster tries an exercise and tells her to imagine it never happened.

Naomi comes to visit and asks for advice on her situation with Emily. Re-enacting Foster's exercise, Effy tells Naomi to imagine that she had never slept with Sophia, and thus none of the events that followed would have ever happened. Naomi does not understand how it would help, as she cannot change what has happened.

Back in Foster's office, Effy is retelling another dramatic incident from her past, but then reveals it to be the ending of the film E.T. the Extra-Terrestrial, her favorite film. Foster tells her she is ready to go home, as long as she sticks to her routine, has no alcohol or drugs and sees him for further counseling sessions twice a week. After she leaves the room, he dances to the song "Easy Lover".

Effy returns to a plain-looking room with a weekly planner on a large whiteboard, as her mother Anthea has tidied everything away. The planner consists of mostly pills, meals, walking, sleeping, counseling and college although there is a small space in the day for Freddie.

Freddie is shocked to see Effy on his doorstep as she brings back his jumper. He asks why she did not let him see her, and she explains it was because of Foster's treatment and how he took all her bad memories and made them good. She says that all she feels for Freddie now is love.

Effy is awoken the next day by a call from an excited Pandora screaming down the phone. They arrive at college, anticipating their final results. Effy asks Doug if she can retake her exams, but he tells her that David Blood wants to see her. Blood tells her that the whole college got A to C grades, as a lot of people took media studies, apart from her. Effy insists she wants to retake the exams but Blood is entirely focused on keeping the college's average grades up so they continue to receive adequate funding. Blood shreds her actual failed results and presents her with new results: A grades in English, Mathematics and French. He tells her that everyone lives and lies and that reality is all relative.

In her next counseling session, Effy tells Foster of her results problem, but he reminds her that they discussed at length that achievement is nothing compared to being happy.

There is heavy rain as the gang gather in Fishponds Tavern to show off their results: JJ with A A B, Naomi with three As, Emily with B B C, Pandora with a C in philosophy, Katie with B C C, Freddie with A C C and Thomas saying he got expelled, which gets him the biggest cheer of the group. Everyone waits for Effy, but she stands up and says that none of it matters to her, and that she has had enough of the group and leaves. She meets Cook outside who says that they have a lot in common. He says that if he was just meeting her now, he would do everything again because he still loves her.

Another counseling session, and Effy describes a room with closed curtains and a man in a chair facing away from her full of hate and death. Foster asks what if he leaves, what if he was never there, and tells her to open the curtains and let the sun shine in.

Freddie waits for Effy at her house and demands and explanation. He reminds her that she told him she loved him the night before she dumped him. He kisses her but Effy tells him to stop, that she went mad when she was with him which is not what love is. Freddie says she makes him mad, which is exactly what love is supposed to do. He leaves and Effy goes upstairs to take her medication. She realizes that her toy giraffe, Patto, is missing and searches frantically for him, emptying out her drawers and wardrobe of her belongings that Anthea tidied away for her. Anthea finds him behind the bed. Effy looks at the mess on her floor, takes her possessions outside and burns them, saying she needs John to make her better.

Effy sits on a bench in the park, and Cook joins her. She says that despite all the times she has passed through the park, she has never noticed the pond. Cook calls her Effy and she asks who that is, saying her name is Elizabeth, and he introduces himself as James.

Later that night they go to a party together, then Effy says she wants to do something bad. They walk past the place where Tony was hit by a bus and all the bad memories come flooding back to Effy. She screams at Cook that it happened, but it never happened, and he hits her. She begs him to hit her again; he does not, so she pushes him to the ground and runs away. He chases after her and finds her standing in the middle of a road shouting that she is not scared, and Cook pushes her out of the way just before she is hit by a van. Lying on the grass, she kisses him then tells him to take her to Freddie, before passing out.

Freddie calls for an ambulance and Cook notices a bag in the corner. Freddie admits that he was going to leave that night because Effy broke his heart. Cook reminds him that she and Freddie have broken his heart, and Freddie has probably broken Effy's heart at some point. Cook leaves telling him to grow up and not screw it up.

Effy wakes up back at the psychiatric hospital with Freddie at her bedside. Foster walks in, and Effy says she doesn't want him any more. Freddie makes him leave. Effy repeatedly tells Freddie that she loves him before she falls asleep and Anthea walks in to take over from him.

The next day, Foster calls Freddie and invites him to his house. They sit in his study to discuss Effy and how she and Anthea disliked his methods. Freddie warns him to stay away and tries to leave, but finds the door locked. Foster tells him that he can't let her have him and approaches him with a baseball bat, beating him to death with it.

Note: The music tracks listed below only refer to the music featured in the episode's initial airing. Many of the music tracks featured in this episode have been substituted for alternative tracks for both the US and UK home media release of Series 4.